Material-handling apparatus for forming pallet loads is well known. For example, in the box-folding industry, corrugated board and boxes are folded into a flat configuration and then stacked to form bundles, which may be either untied or tied. The bundles are then arranged into layers in any desired pattern, and then the layers are stacked on a pallet for shipment.
In one palletizing system presently being used, the bundles are supplied by an inclined conveyor to a downstacker having a retractable plate for receiving and depositing layers or bundles onto the downstacker to form the desired stack. Typically, a worker is located at the downstacker on an elevated platform and operates to arrange the bundles supplied by the inclined conveyor in the desired pattern on the retractable plate. Then, the worker operates to retract the plate so that the layer of bundles is deposited onto the downstacker. In such systems, a worker is also required to be stationed at the input end of the inclined conveyor in order to insure that the bundles are properly transferred thereto from previous work stations and also to insure that untied bundles disposed on the inclined conveyor do not topple over.
Accordingly, it would be highly desirable to provide a palletizing system which eliminates the need for a worker at the downstacker, in addition to the worker at the input end of the inclined conveyor and also allows higher bundles to be employed.
Broadly, it is an object of the present invention to provide a palletizing system and control therefor which overcomes one or more of the problems of present palletizing systems. Specifically, it is within the contemplation of the present invention to provide a palletizing system which automatically transfers layers of one or more bundles from a loading conveyor to a downstacker and forms the layers into stacks on pallets.
It is a further object of the present invention to provide a palletizing system for coordinating and synchronizing the various functions of supplying bundles to a loading conveyor, arranging the bundles into layers, transferring the layers of bundles to a downstacker, forming the layers into stacks on pallets, strapping the stack, and discharging the loaded pallet ready for shipment.
It is a still further object of the present invention to provide a palletizing system which is controlled to intermittently stop the loading conveyor and vertical conveyor while a formed stack is being transferred to the discharge position of the downstacker and then discharged for shipment.
It is a still further object of the present invention to provide an improved palletizing system which eliminates the need for a worker positioned at the downstacker, since in the present invention, the bundles are formed into layers by a worker positioned at the infeed end of the system rather than at the downstacker.
It is still further object of the present invention to provide an improved palletizing system which employs a vertical conveyor having horizontally-disposed carriers which always maintain the layers in a horizontal orientation and, therefore, eliminates the need for inclined conveyors which have the inherent drawback that high bundles tend to topple over.